The present invention relates to a process for forming magnetic latent images with a magnetic copying apparatus. More particularly, the invention relates to a process of forming magnetic latent images by heating a magnetic recording body in the pattern of an image and bringing the magnetic recording body into contact with a master magnetic body having a previously magnetized uniform pattern for thermal and magnetic image transfer.
In a magnetic copying apparatus, a magnetic body is magnetized in the pattern of an image to form a magnetic latent image, which is developed by a magnetic toner composed of a macromolecular resin containing minute magnetic particles which serve as magnetic field-sensitive colored particles. The particles forming the latent image are electrostatically or magnetically transferred to a sheet of paper or the like and fixed with heat and pressure to form a permanent picture image. After the residual magnetic toner has been removed, the magnetic body serving as a magnetic latent image carrier either enters a next development cycle or is demagnetized to eliminate the magnetic latent image for the formation thereon of a next new magnetic latent image to repeat the same process.
In such a process of forming magnetic latent images, it has been customary to position a magnetic head adjacent to the magnetic latent image carrier and supply the magnetic head with a recording current responsive to a picture image signal to magnetize the magnetic latent image carrier.
To form a magnetic latent image fully across the width of the image on the magnetic latent image carrier with the magnetic head, a magnetic recording track having a single or plurality of magnetization printing units is used to effect both successive recording along the direction of movement of the magnetic latent image carrier (main scanning) and traverse scanning (auxiliary scanning) in a direction normal to the direction of movement of the carrier for magnetic recording.
Such a recording process requires a precision drive and control system for maintaining a constant auxiliary scanning line interval and for providing a variety of modes of operation such for example as rapid travel of the magnetic latent image carrier to reduce the scanning time, and slow travel of the carrier for imaging operations such as development and transfer of the image.
An array of multiple magnetic heads has also been proposed which provides magnetic recording tracks arranged fully across the image width which are close enough together to provide a desired resolving power for a reproduced picture image in which one line at a time is recorded as the magnetic latent image carrier moves. With the array of multiple magnetic heads, however, it is necessary to arrange narrow recording tracks about 100 .mu.m wide or less at intervals of about 100 .mu.m to meet the desired image resolution. In addition, the coils provided for each recording track should have a sufficient number of windings to reduce the needed recording current to an acceptable value. As these complicated structures are necessarily small in size, electromagnetic interference between adjacent tracks renders the construction of an array of multiple magnetic heads infeasible.